The risk of infection with Staphylococcus aureus bacteraemia may have a genetic component, Danish research suggests.

The population based registry study published in the Annals of Internal Medicine showed that having a first degree relative who had been hospitalised with S aureus bacteraemia more than doubled a person’s risk for the disease.

The risk was significantly higher if the infected patient was a sibling (5.01 (3.30 to 7.62)) rather than a parent (1.96 (1.45 to 2.67); P<0.001).

The authors said that the results were unlikely to be explained by direct transmission because more than 80% of exposed people who acquired S aureus bacteraemia were infected with a different strain from that of the infected relative.